JPH11129105A - Spindle structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount a tool shank even for one-face constraint with two-face constraint. SOLUTION: A front end face 2c is formed at the front end of a spindle mainbody 2 and a tapered cap 5 is provided in the spindle mainbody 2 to be axially movable between a stand-by position TP and a constraint position KP, the tapered cap 5 having a wedge portion 6 at the front end to be elastically expandable and deformable, a tapered face 5b being formed on the inner periphery of the wedge portion 6 to form a tapered portion insert space 12 therewith and an outer periphery 5a being formed on the outer periphery of the wedge portion 6 to be freely put in contact with the inner periphery 2b of the spindle mainbody 2, so that the end face 26 is brought into contact with the front end face 2c and the tapered face 22a is brought into contact with the tapered face 5b when a shank 21 is mounted and held on a spindle 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle structure for a spindle, such as a machining center, in which a tool can be suitably mounted on the spindle.

[0002]

2. Description of the Related Art As a method of mounting a tool to a spindle such as a machining center, a method of closely contacting a tapered surface of the tool shank with a spindle has been adopted. Recently, not only the taper surface is brought into close contact with the main shaft side, but also a method in which the end surface of the tool shank and the end surface of the tip end of the main shaft that are opposed to each other in the axial direction of the main shaft are brought into close contact with each other, that is, a mounting method by two-surface constraint. Spreading.

[0003]

The adoption of the two-plane constraint as described above has advantages such as high rigidity and high-speed rotation. Therefore, mounting by only the close contact through the tapered surface ( Attempts have been made to mount a tool shank, which was previously made to perform one-face restraint, on a spindle with two-face restraint. However, the structure of the tool shank and the spindle that adopts the two-sided constraint is usually significantly different from the structure of the tool shank and the spindle before the one-sided constraint is adopted. It was difficult to attach to the main shaft due to restraint.

In view of the above circumstances, an object of the present invention is to provide a main shaft structure that can be mounted even with a tool shank for one-plane restraint by two-plane restraint.

[0005]

That is, a first aspect of the present invention has a cylindrical main spindle body (2) provided on a machine tool so as to be rotatable about a shaft, and a tool ( 27) and a holder part (25) to which the holder part (2) can be attached.
5) an insertion tapered portion (22) provided on the rear end side;
A pull stud provided on a rear end side of the insertion tapered portion; a holder end surface facing the rear end side is formed on the holder portion; A tool shank (21) having a constraining tapered surface (22a) formed on the outer periphery of (22) is inserted into the insertion taper portion (2).
2) is inserted into the spindle main body (2) from the front end side of the spindle main body (2), and the pull stud (23) is inserted.
The main shaft (1) is adapted to be mounted so as to be engaged with a predetermined tool shank engaging / retracting means (3) so as to be pulled in the axial direction. A surface (2c) is formed, and a tool restraining member (5) is placed in the spindle main body (2) in a restraint release position (T
P) and a restraining position (KP) on the tip end side of the spindle main body (2) with respect to the restraint releasing position (TP). The tool restraining member (5) is provided so as to be movable in the axial direction. A taper restricting portion (6) formed annularly along the inner periphery of the main spindle body (2) and elastically expandable and deformable in a radial direction on a distal end side of the restricting member (5); A taper contact surface (5b) is provided on the inner peripheral side of the taper restraining portion (6).
The taper contact surface (5b) is formed so as to form an insertion taper portion receiving space (12), and the main spindle body contact restricting surface (5a) is provided on the outer peripheral side of the taper restricting portion (6). The tool shank (21) is formed so as to be able to abut on the inner peripheral surface (2b) of (2), and is provided with a movement drive means (10) capable of axially moving and driving the tool restraining member (5). When mounting and holding on the main shaft (1), the holder end surface (26) is brought into contact with the holder end surface contact surface (2c), and the restraining taper surface (22a) is brought into contact with the taper contact surface. (5b).

According to a second aspect of the present invention, in the main spindle structure according to the first aspect, a slit (9) is formed in the taper restraining portion (6).

According to a third aspect of the present invention, in the spindle structure according to the first aspect, an outer diameter (D4) of the tapered restraining portion (6) in a natural state is an inner diameter (A) of a corresponding portion of the spindle main body (2). D1).

Note that the numbers in parentheses and the like are for convenience showing corresponding elements in the drawings, and therefore, the present description is not limited to the description on the drawings.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an example of the main shaft structure according to the present invention.

A spindle 1 of a machining center (not shown in its entirety) has a sleeve-shaped spindle main body 2 extending in the directions of arrows A and B in the left-right direction of FIG. The shaft center can be driven to rotate around the shaft center CT1 in the directions indicated by arrows S and T with respect to a headstock (not shown) or the like in the machining center. Spindle body 2
Is provided with a known collet device 3 concentrically with the axis CT1. The collet device 3 is a known drawbar (not shown) connected to the rear side of the collet device 3 (that is, the arrow B side). And a known drawbar drive actuator connected to the drawbar so that the drawbar can be moved and driven in the directions of arrows A and B, and can be freely engaged and disengaged with the pull stud 23 of the tool unit 20 described later. .

In the interior 2a of the spindle main body 2, the shaft center CT is provided.
1 is provided with a tapered cap 5 which is basically formed in an annular shape around the center 1, and the inner diameter of the tapered cap 5 is increased on the inner peripheral side in the direction of the arrow A in the drawing, which is the tip direction of the main shaft. A tapered surface 5b is formed. The tapered surface 5b and the outer peripheral surface 5a of the tapered cap 5 form a wedge portion 6 having a wedge-shaped cross section near the tip of the tapered cap 5. A tapered portion insertion space 12 is formed on the inner peripheral side of the wedge portion 6 so as to be surrounded by the tapered surface 5b. A portion of the taper cap 5 on the rear side (arrow B side) of the wedge portion 6 is a connection portion 7, and the connection portion 7 of the collet device 3 located on the inner peripheral side of the connection portion 7. It has a substantially cylindrical shape that does not interfere with movement. The taper cap 5 is located in the interior 2a of the spindle main body 2 in a direction parallel to the axis CT1 with respect to the spindle main body 2, that is, an arrow A in FIG.
It is movable in the direction B between a standby position TP (shown by a two-dot chain line) and a restraint position KP on the distal end side (that is, the arrow A side). Note that the taper cap 5 is indicated by arrows A and B
When moving in the direction, the front end 6a of the wedge portion 6 (therefore, the front end of the taper cap 5) is always larger than the opening 2d in which the inside 2a of the main spindle body 2 opens in the direction of arrow A at the front end of the main spindle body 2. The rear end 6b (i.e., the end on the arrow B side) of the wedge portion 6 is always located at the front end side of the main shaft (i.e., the arrow in the figure) with respect to the collet device 3 described above. A side).

The taper cap 5 has a slot 9 extending in the directions of arrows A and B extending from the tip 6a of the wedge 6 to the connecting portion 7 in a radial direction around the axis CT1 inside and outside the ring of the taper cap 5. A plurality of slits 9 are provided so as to penetrate (only one slit 9 is shown in FIG. 1), and the plurality of slits 9 are arranged at a predetermined angular pitch about the axis CT1. I have. In the state shown in FIG.
In the taper cap 5, the vicinity of the wedge portion 6 is elastically expanded and deformed by using the plurality of slits 9 described above, and the outer peripheral surface 5 near the expanded and deformed wedge portion 6 is formed.
a is in contact with the inner peripheral surface 2b of the main spindle body 2 by surface contact. Accordingly, the outer diameter D4 of the tapered cap 5 in a natural state (shown by a two-dot chain line in FIG. 1) that is not expanded and deformed is slightly smaller than the inner diameter D1 of the corresponding portion of the inside 2a of the main spindle body 2. . On the other hand, the tapered cap 5 is connected to the rear end of the connecting portion 7 (that is, the end on the arrow B side) and extends the inside 2a of the spindle main body 2 in the directions of arrows A and B (see FIG. 2). (Only some of them are shown).
An actuator (not shown) for driving a taper cap, which is a known hydraulic actuator or the like, is provided on the rear end side (that is, the arrow B side) of the connection driving member 10. That is, the coupling driving member 1 is driven by the taper cap driving actuator.
0 is driven to move in the inside 2a of the main spindle body 2 in the directions of arrows A and B, and the driving of the connection driving member 10 causes the taper cap 5 to move inside the main spindle body 2.
a is driven to move in the directions of arrows A and B.

The above-described main spindle 1 is provided with a tool unit 20 for one-surface restraint (that is, a tool unit 20 of a type which has been widely used in the past, which is constructed so as to be mounted only by close contact with the main spindle side via a tapered surface). ) Is attached. As shown in FIG. 1 (a side view of the tool unit 20 is shown), the tool unit 20 mounted on the spindle 1 has an axis CT
1 and are basically extended in the directions of arrows A and B in the figure. That is, the tool unit 20 has a shank 21, and the shank 21 has a conical tapered portion 22 whose outer diameter increases in the tool tip direction (the direction of arrow A). The tapered portion 22 is formed in the tapered portion insertion space 1 in the wedge portion 6 of the tapered cap 5 described above.
2, the tapered surface 22a, which is the outer peripheral surface of the tapered portion 22, is in contact with the tapered surface 5b of the wedge portion 6 by surface contact. A known pull stud 23 is provided at the rear end (the end on the arrow B side) of the tapered portion 22. In the state shown in FIG. 1, the pull stud 23 is engaged and gripped by the collet device 3. . The front end (the end on the arrow A side) of the tapered portion 22 has a tapered shape whose length in the direction of the axis CT1 is the length Lx.
A flange portion 25 is provided via a flange connection portion 29, and the above-described tapered portion 22, pull stud 23, and tapered flange connection portion 29 are inserted and arranged in the inside 2 a of the main spindle body 2. That is, the maximum outer diameter D2 of the tapered portion 22 and the tapered flange connecting portion 29 (the outer diameter at the tapered flange connecting portion 29 in the present embodiment) is the inner diameter D1 of the inside 2a of the main spindle body 2 and the opening 2d. Is smaller than.

An engaging groove 25a is formed on the outer peripheral side of the flange portion 25 so as to be freely engageable with a tool gripping arm or the like of an automatic tool changing device (not shown). The outer diameter D3 at the rear end 25b (the end on the arrow B side) of the flange portion 25 is sufficiently larger than the maximum outer diameter D2 of the tapered flange connecting portion 29, and the difference between these outer diameters D2 and D3 is caused. An annular end surface 26 is formed at the rear end 25b of the flange portion 25 so as to face rearward (that is, in the direction of arrow B). The outer diameter D3 of the rear end 25b is equal to the inner diameter D of the opening 2d of the main spindle body 2.
1, the entire flange portion 25 is disposed outside the opening 2 d of the main spindle body 2 (on the arrow A side). At the tip of the main spindle body 2, a tip end face 2 c is formed around the opening 2 d so as to face in the direction of arrow A. The tip end face 2 c and the end face 26 of the flange portion 25 are It is in a state of contact by surface contact. A tool 27 such as a drill or an end mill is provided concentrically with the axis CT1 on the front side (arrow A side) of the shank 21.

Since the main shaft 1 and the like are configured as described above, to mount the tool unit 20 on the main shaft 1, first, the engaging groove 25 a is formed by the tool gripping arm or the like by an automatic tool changing device (not shown). As shown in FIG. 1, the tool unit 20 that is engaged and gripped via the pull stud 23 and the tapered portion 22 is installed in a manner that the pull stud 23 and the tapered portion 22 side are inserted into the interior 2 a from the opening 2 d of the main spindle body 2 in the arrow B direction. This tool unit 2
The collet device 3 is driven in such a manner that a draw bar driving actuator (not shown) is driven by a draw bar driving actuator (not shown) together with the insertion installation of the main body 2 so that the internal
a to the collet device 3
Engage and grip with. Subsequently, the collet device 3 is pulled in the direction of arrow B by further driving a drawbar (not shown) with a drawbar drive actuator (not shown).
By this retraction, the entire shank 21 is moved through the arrow B via the pull stud 23 gripped by the collet device 3.
Direction, the end face 26 of the flange portion 25 is pressed against the tip end face 2 c of the main spindle body 2, and these end faces 26
And the front end face 2c are in close contact with each other. At this point, the taper cap 5 is in the standby position TP, which is the rearmost side (the arrow B side).
(Shown by a two-dot chain line), and even if the tapered portion 22 of the shank 21 is pulled in the direction of arrow B inside the spindle main body 2 and thus inside the tapered cap 5 as described above, The part 22 and the wedge part 6 of the taper cap 5 hardly come into contact with each other. That is, when the shank 21 is pulled in the direction of the arrow B, it is not necessary to receive the reaction force (that is, the force in the direction of the arrow A) from the taper cap 5, so that the end surface 26 of the flange portion 25 and the front end surface of the spindle body 2 are not required. 2c is effectively pressed, and the close contact between these end surfaces 26 and the front end surface 2c is ensured.

Thereafter, while the pulling of the shank 21 in the direction of arrow B is continued through the collet device 3 and the like, the connecting drive member 10 is moved and driven in the direction of arrow A by a taper cap driving actuator (not shown). The cap 5 is pressed and driven in the direction of arrow A. Thus, the wedge portion 6 of the taper cap 5 comes into contact with the tapered surface 22a of the tapered portion 22 via the tapered surface 5b. Subsequently, the taper cap 5 is disposed in the restraining position KP by pressing and driving in the direction of arrow A. That is,
The wedge portion 6 is elastically expanded and deformed by using the plurality of slits 9 and bites in the direction of arrow A between the main spindle body 2 and the tapered portion 22 by using the wedge shape. Thus, the tapered surface 5b of the tapered cap 5 and the tapered surface 22a of the tapered portion 22 are pressed and adhered, and the outer peripheral surface 5a near the wedge portion 6 is pressed.
And the inner peripheral surface 2b of the spindle main body 2 were pressed and contacted. Thus, the mounting of the tool unit 20 on the main shaft 1 is completed. In addition,
Since the force for pulling the shank 21 in the direction of arrow B via the collet device 3 or the like is set to be sufficiently larger than the force for pressing the taper cap 5 in the direction of arrow A, the force for pressing the taper cap 5 in the direction of arrow A. Is not so large that the flange portion 25 of the shank 21 is separated from the distal end surface 2c of the spindle main body 2 or the pressure contact between the end surface 26 of the flange portion 25 and the distal end surface 2c is not released. Further, since the wedge portion 6 is elastically expanded and deformed, the restoring force due to this expanded deformation acts on the tapered portion 22 of the shank 21 in contact with the wedge portion 6. Thereby, the taper cap 5 and the shank 2
The press-contact between the two is effectively performed.

It is known that the length Lx of the taper / flange connection portion 29 of the tool unit 20 described above is different depending on each tool. Therefore, when the end surface 26 of the flange portion 25 is to be brought into close contact with the tip end surface 2c of the spindle main body 2 as in the present embodiment, the position of the taper portion 22 in the spindle main body 2 is changed by the individual tool. -It shifts in the direction of arrow A, B by the difference of length Lx of the flange connection part 29. However, the main spindle body 2 and the tapered portion 22
Since the taper cap 5 biting between the two is movable and movable in the directions of the arrows A and B, the position of the tapered portion 22 is shifted in the directions of the arrows A and B, so that the biting position of the taper cap 5, and thus the constraint position KP Are shifted in the directions of the arrows A and B, so that the pressure-contact state between adjacent ones of the main spindle body 2, the taper cap 5, and the taper portion 22 is constant regardless of the length Lx of the taper / flange connection portion 29. Become. In other words, the versatility of the tool is very high because the mounting of the tool unit can be reliably performed in a certain condition for various tools.

After the tool unit 20 is mounted as described above, the spindle unit 2 is rotationally driven to rotate the tool unit 20 (at this time, the collet device 3 is moved together with the spindle unit 2).
The taper cap 5 and the like also rotate), and machining is performed by a tool 27 provided in the tool unit 20. As described above, the shank 21 of the tool unit 20 is pressed against the end face 26 of the flange portion 25 and the tip end face 2 c of the main spindle body 2, and the taper cap 5.
Are constrained integrally to the main shaft 1 by press contact (indirect press contact) between the main spindle body 2 and the tapered portion 22 having the shape interposed therebetween, which is constrained by the end face 26 and the tapered face 22a. It is a two-sided constraint. In the two-plane constraint, higher rigidity can be ensured compared to the case of using the one-plane constraint, and the high-speed rotation can be supported. Therefore, the tool unit 20 for the one-plane constraint is mounted by the two-plane constraint. It can be convenient. In addition, a portion that comes into contact with the tapered portion of the shank, for example, a tapered inner peripheral surface of the main spindle body is easily damaged in the case of a conventional main spindle, and a large amount of work such as replacing the main spindle main body is required for repair. In this embodiment, the taper cap 5 that comes into contact with the tapered portion 22 of the shank 21 is separate from the main spindle body 2. Therefore, even if the taper cap 5 is damaged, only the taper cap 5 needs to be replaced. Can be repaired and work is simplified.

[0019]

As described above, the first aspect of the present invention has a main spindle main body such as a cylindrical main spindle main body 2 provided on a machine tool so as to be rotatable and rotatable. Tool 27
Such as a flange portion 25 to which a tool such as a tool can be attached, and a tapered portion 22 provided on the rear end side of the holder portion.
And a pull stud such as a pull stud 23 provided on a rear end side of the insertion taper portion, and a holder end surface such as an end surface 26 facing the rear end side is formed on the holder portion. Inserting a tool shank, such as a shank 21 having a tapered surface for restraint such as a tapered surface 22a on the outer periphery of the insertion taper portion, into the spindle body from the tip side of the spindle body while inserting the insertion taper portion into the spindle body; The pull stud is engaged by a predetermined tool shank engaging and retracting means such as a collet device 3, a draw bar (not shown), a draw bar driving actuator (not shown), and the like, and is attached so as to be pulled in the axial direction. On the spindle, a holder end face contact surface such as a tip end face 2c is formed at a tip end of the spindle main body, and a tool constraint such as a taper cap 5 is formed in the spindle main body. A material is provided movably in the axial direction between a restraint release position such as a standby position TP and a restraint position such as a restraint position KP which is on the distal end side of the spindle main body with respect to the restraint release position. A wedge portion 6 is formed on the tip end side of the tool restraining member along the inner periphery of the spindle main body, and is elastically expandable and deformable in a radial direction.
The tapered contact surface such as the tapered surface 5b is formed on the inner peripheral side of the tapered restricted portion, and the insertion tapered portion receiving space such as the tapered portion insertion space 12 is formed by the tapered contact surface. Forming a main body contacting restricting surface such as an outer peripheral surface 5a on the outer peripheral side of the taper restricting portion in such a manner as to freely contact an inner peripheral surface such as an inner peripheral surface 2b of the main spindle body; A coupling driving member 10 capable of moving and driving the tool restraining member in the axial direction, and a moving driving means such as an actuator (not shown) for driving a taper cap are provided. The tool shank is restrained with respect to the main shaft by contacting the taper surface for restraint with the taper contact surface while being in contact with the holder end face contact surface. Contact with In addition to the above constraint, the taper restraining portion restrained to the spindle body side by the contact between the spindle body contact restraining surface and the inner peripheral surface of the spindle body is restrained by the contact between the restraining taper surface and the taper contact surface. Is a two-sided constraint. In the two-plane restraint, a higher rigidity can be ensured compared to the case of using the one-plane restraint, and a high-speed rotation can be supported. Therefore, the tool shank for the one-plane restraint is mounted by the two-plane restraint. It can be convenient. In addition, the portion that comes into contact with the insertion taper portion of the tool shank, for example, the tapered inner peripheral surface of the spindle main body in the case of a conventional spindle is easily damaged. Although work was required, in the present invention, since the tool restraining member that comes into contact with the insertion taper portion of the tool shank is separate from the main spindle body, even if the tool restraining member is damaged, only the tool restraining member needs to be replaced. Can be repaired and work is simplified.

According to a second aspect of the present invention, in the spindle structure according to the first aspect of the present invention, a slit such as a slit 9 is formed in the tapered restricting portion. This is done effectively in the form of Therefore, in addition to the effect of the first aspect, the tapered restraint portion is effectively deformed according to the shape of the insertion taper portion and the like. The contact with the inner peripheral surface of the spindle main body is reliably performed together, and a highly reliable constraint is realized.

According to a third aspect of the present invention, in the spindle structure according to the first aspect of the present invention, an outer diameter such as an outer diameter D4 of the tapered restraining portion in a natural state is larger than an inner diameter such as an inner diameter D1 of a corresponding portion of the main spindle body. Therefore, the degree of deformation in the expansion deformation of the tapered restraint portion is ensured by utilizing the difference between the diameters. Therefore, in addition to the effect of the first invention, the taper restraining portion can be expanded and deformed when the tool shank is mounted by an amount corresponding to the degree of deformation secured, and the restoring force causes the taper restraining portion to be inserted between the taper restraining portion and the insertion taper portion. This is convenient because the restraint is ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a spindle structure according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Spindle 2 ... Spindle main body 2b ... Inner peripheral surface 2c ... Holder end surface contact surface (tip end surface) 3 ... Tool shank engagement retracting means (collet device) 5 ... Tool restraining member (taper cap) 5a ... spindle main body contact restricting surface (outer peripheral surface) 5b ... taper contact surface (taper surface) 6 ... taper restricting portion (wedge portion) 9 ... slot 10 ... moving driving means (connection driving member) 12 insertion taper part receiving space (taper part insertion space) 21 tool shank (shank) 22 insertion taper part (taper part) 22a taper surface for constraining (taper surface) 23 pull stud 26 … Holder end face (end face) 25… Holder part (flange part) 27… Tool D1… Inside diameter D4… Outside diameter KP… Constraint position TP… Constraint release position (standby position)

Claims (3)

[Claims] 1. A holder having a cylindrical main spindle body provided on a machine tool so as to be rotatable and rotatable, wherein a tool is freely mounted on a tip end side, and a holder is provided on a rear end side of the holder section. And a pull stud provided on a rear end side of the insertion taper portion, a holder end surface facing the rear end side is formed on the holder portion, and a restraint is provided on an outer periphery of the insertion taper portion. A tool shank having a tapered surface is inserted into the spindle main body from the tip end side of the spindle main body, and the pull stud is engaged with a predetermined tool shank engaging and retracting means in the axial direction. A main shaft adapted to be attached by being drawn into the main body, forming a holder end surface abutting surface at a tip end of the main body, a tool restraining member in the main body, a restraining release position,
The tool restraining member is provided movably in the axial direction between a restraining position on the distal end side of the spindle main body from the restraining release position, and the tool restraining member is disposed on the distal end side of the tool restraining member along the inner periphery of the spindle main body. A taper restraining portion formed in an annular shape and elastically expandable and deformable in a radial direction; a taper contact surface on an inner peripheral side of the taper restraining portion; an insertion taper portion receiving space formed by the taper contact surface; Forming a main body contacting constraining surface on the outer peripheral side of the taper restricting portion so as to be able to abut on the inner peripheral surface of the main spindle main body; and moving the tool restricting member in the axial direction. Providing a movable drive means that can be driven, when mounting and holding the tool shank on the main shaft,
A spindle structure in which the holder end surface is brought into contact with the holder end surface contact surface, and the restricting tapered surface is brought into contact with the tapered contact surface. 2. The main shaft structure according to claim 1, wherein a slit is formed in said taper restraining portion. 3. The main shaft structure according to claim 1, wherein an outer diameter of said taper restraining portion in a natural state is smaller than an inner diameter of a corresponding portion of said main spindle body.